From: Baokun Li libaokun1@huawei.com
commit 0aeaa2559d6d53358fca3e3fce73807367adca74 upstream.
When a backup superblock is updated in update_backups(), the primary superblock's offset in the group (that is, sbi->s_sbh->b_blocknr) is used as the backup superblock's offset in its group. However, when the block size is 1K and bigalloc is enabled, the two offsets are not equal. This causes the backup group descriptors to be overwritten by the superblock in update_backups(). Moreover, if meta_bg is enabled, the file system will be corrupted because this feature uses backup group descriptors.
To solve this issue, we use a more accurate ext4_group_first_block_no() as the offset of the backup superblock in its group.
Fixes: d77147ff443b ("ext4: add support for online resizing with bigalloc") Signed-off-by: Baokun Li libaokun1@huawei.com Reviewed-by: Jan Kara jack@suse.cz Cc: stable@kernel.org Link: https://lore.kernel.org/r/20221117040341.1380702-4-libaokun1@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/resize.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1567,8 +1567,8 @@ exit_journal: int meta_bg = ext4_has_feature_meta_bg(sb); sector_t old_gdb = 0;
- update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es, - sizeof(struct ext4_super_block), 0); + update_backups(sb, ext4_group_first_block_no(sb, 0), + (char *)es, sizeof(struct ext4_super_block), 0); for (; gdb_num <= gdb_num_end; gdb_num++) { struct buffer_head *gdb_bh;
@@ -1775,7 +1775,7 @@ errout: if (test_opt(sb, DEBUG)) printk(KERN_DEBUG "EXT4-fs: extended group to %llu " "blocks\n", ext4_blocks_count(es)); - update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, + update_backups(sb, ext4_group_first_block_no(sb, 0), (char *)es, sizeof(struct ext4_super_block), 0); } return err;